Remove wrong constness from the git diff parsing code.
Remove wrong constness from the git diff parsing code.

* subversion/libsvn_diff/parse-diff.c
  (struct transition): The callback function needs a char * for input,
   not a const char *. Some implementations modify input in place.
  (diff_minus, diff_plus, git_start, git_minus, git_plus, git_move_from,
   git_move_to, git_copy_from, git_copy_to, git_new_file, git_deleted_file):
   Remove 'const' from 'line' parameter to allow these functions to modify
   it in place, as some already do. Remove related '###' comment from git_plus.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1129795 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion